Abstract: Selecting three main intensive cropping systems of North China,i.e,wheatmaize rotation,plastic greenhouse vegetable,and apple orchard as test objectives,this paper studied their nitrogen (N) budget,soil nitrate-N accumulation,and year-round dynamics of groundwater nitrate-N concentration. The results showed that in plastic greenhouse vegetable cropping system,the annual N input from chemical fertilizers,manure,and irrigation was 1 358,1 881 and 402 kg·hm^-2,being 2.5,37.5 and 83.8 folds of the corresponding items in wheat-maize cropping system,and 2.1,10.4 and 68.2 folds in orchard,respectively,and its total N input amounted to 3 656 kg·hm^-2,being 5.8 times of the wheat-maize cropping system,and 4.2 times of the orchard.The wet deposition N in the three cropping systems ranged from 14.2 kg·hm^-2 to 18.9 kg·hm^-2.The N output by wheat-maize, greenhouse vegetable and orchard was 280,329 and 121 kg·hm^-2,the N surplus was 349,3 327 and 746 kg·hm^-2,and the remained nitrate-N after harvest amounted to 221～275，1 173 and 613 kg·hm^-2 in 0～90 cm soil layer,and 213～242,1 032 and 976 kg·hm^-2 in 90～180 cm soil layer, respectively. Crop field had a comparatively even distribution of nitrate N in its 0～180 cm soil profile,and a sharp increase of nitrate N throughout the soil profile were found in both greenhouse vegetable and orchard fields.There was an evident nitrate leaching in all three cropping systems.The groundwater in shallow well (<15 m) was severely contaminated in greenhouse vegetable area,with the nitrate-N concentration in 99% of the samples exceeding the maximum permissible limit for drinking water (10 mg·L^-1),while 5% of the samples in deep well in vegetable area and in shallow well in orchard and 1% of the samples in deep well in wheat-maize field were exceeded the limit.The nitrate-N concentration exponentially decreased with well depth (m) in greenhouse vegetable area.

Key words: Broadleaved Korean pine forests, Eco climatic suitability, Temperature water effect function, Climate change, Assessment